This thesis presents results for the extraction, purification and chemical characterisation and quantification of cyclic peptides. The thesis is divided into six chapters including a general introduction, the materials and methods used, in addition to three chapters with detailed experimental results and a chapter on enzyme chemistry. The first part presents data of a chemically synthesized analogue of a natural product myriastramide C which contains its full structural elucidation and comparison of data obtained to that of the natural product reported in literature. The second part discusses enzyme chemistry, chemical characterisation results of natural, new modified heterocyclic peptides produced in vitro and through chemo enzymatic reactions using genetically modified enzymes. Results presented include mass spectroscopic data and NMR structural characterisation for these peptides. The third section presents data for the quantification of heterocyclic peptides using high pressure liquid chromatography coupled in parallel to electrospray mass spectrometer and inductively coupled plasma (HPLC-ICP-MS), their quantification was achieved using their sulfur content without authentic standards. Naturally occurring cyclic peptide were also quantified using proton nuclei magnetic resonance (qNMR) with a non peptidic ERETIC reference material. In conclusion, this work highlights the possibility of multi-disciplinary science in the production of synthetic and semi-synthetic compounds through the use of enzymes. It is possible to produce new analogs of natural products, hence, providing an avenue for increasing the library of new compounds. Accurate quantification of these compounds is also essential for the acquisition of proper pharmacokinetic data for these new compounds so that unambiguous biological data can be obtained.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:723247 |
| Date | January 2017 |
| Creators | Adaba, Rosemary Isioma |
| Publisher | University of Aberdeen |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://digitool.abdn.ac.uk:80/webclient/DeliveryManager?pid=233135 |
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